The enthalpy of formation of CO2 at 25oC is - 393.51 kJ/mol. What is the enthalpy of formation at 500 oC?

-375.9_KJ / (mol)

Explanation:

H (T2) ≈ H (T1) + CPΔT

Specific heat of Carbon is 0.71 J/g K.

At 283.15 the heat capacity is 37.12 J / (mol*K)

Kirchhoff's law

H (T2) ≈ H (T1) + CPΔT

Where

H (T1) and H (T2) are the heat of formation of CO2 at temperatures T1 and T2

CP is the heat capacity

Thus we have and ΔT is the temperature change

H (T2) ≈ - 393.51*10^3+CP * (500-25)

= - 393.51*10^3+37.12 * (500-25)

= - 375878 J / (mol)

= - 375.9KJ / (mol)